awaforge

mdWalker

AGPL-3.0-onlyRelease 2L4

Visitor walker enter/exit with .use(...) for extensions.

Module mdWalker | Source packages/front/office/md/src/md-walker.js | Deps mdNode | Worker-safe yes

Visitor-style walker mirroring ooxml's docxWalker. Dispatches enter / exit per node type, supports a '*' wildcard, and exposes ctx.stop() / ctx.skipChildren() for traversal control. An instance can accumulate extensions via use(...) and merges them automatically.

Resolve

import { runtime } from '@awacloud/fw';
import { fw_require, modules } from '@awacloud/md';
runtime.registerAll(fw_require);
runtime.registerAll(modules);

const mdWalker = runtime.resolve('mdWalker');
// { createWalker, walk }
const w = mdWalker.createWalker();

The factory itself doesn't consume its declared mdNode dependency (WalkerLocal is self-contained), so mdWalker.factory() also works without DI, if imported directly via import { mdWalker } from '@awacloud/md' (the raw descriptor).

API

Method Signature Returns
walk (root, visitors) => void One-shot walk, top-level helper
createWalker() () => Walker Instance with .use() + .walk()

Walker instance

Method Signature Returns
use (...exts: {visitors}[]) => void Registers visitors
walk (root, extraVisitors?) => void Runs, merging ext visitors + extra
extensions getter ⇒ Array Copy of the extensions
hasExtensions getter ⇒ boolean —

visitors shape

const visitors = {
    heading: { enter(node, ctx) { /* … */ }, exit(node, ctx) { /* … */ } },   // any node type: 'link', 'code_block', …
    '*':     { enter(node, ctx) { /* … */ } }                                  // optional wildcard
};

ctx shape

Field Description
depth Nesting depth (root = 0)
parent Parent node (null at root)
stop() Aborts the whole traversal
skipChildren() Skips descending into the current node

Examples

Case 1 — one-shot walk

import { runtime } from '@awacloud/fw';
import { fw_require, modules } from '@awacloud/md';
runtime.registerAll(fw_require);
runtime.registerAll(modules);

const md       = runtime.resolve('md');
const mdWalker = runtime.resolve('mdWalker');

const ast = md.parse('# h1\n\n## h2');
mdWalker.walk(ast, {
    heading: {
        enter(n) { console.log('H' + n.level); }
    }
});
// H1
// H2

Case 2 — instance with extensions

const w = mdWalker.createWalker();
w.use({ visitors: { link: { enter(n) { console.log(n.destination); } } } });
w.walk(ast);

Notes

  • For leaves (text, code, softbreak, …), only enter is emitted.
  • ctx.skipChildren() only works on containers (isContainer === true).
  • walk() (top-level) has no extensions registry — use createWalker() for that.
  • Extension order is preserved: the first registered runs first on enter, last on exit (LIFO).

See also